Carburetor



Aug- 13, 1957 J. J. cREEcH 2,802,651

CARBURETOR Filed July sl, 1953 77 73 JESSE J. CREECH,

7.6' INVEN TOR. 7 12 K 4 W B W ATTORNEK CARBURETR Jesse J. Creech, Inglewood, Calif.

Application July 31, 1953, Seria! No. 371,669

2 Claims. (Cl. 2451-50) This invention relates to carburetors for use in the air intake of an internal combustion engine and is directed to the problem of providing highly efficient carburetion under all Operating conditions, as well as the problem of sirnplifying the construction of such a carburetor, with special reference to simplification of the working parts.

In general the basic combination employed in a carburetor for use at the air intake of an internal combustion engine comprises a body or housing having a main passage for the air intake stream, a throttle, a throttle valve to variably restrict the main passage for control of the air stream and, finally, means to introduce fuel, usually in jet form, into this main passage. In a simple conventional carburetor, for example, the main passage may be constructed to form a venturi throat on the intake side of the throttle valve and a nozzle or jet discharges fuel into this throat either laterally thereof or in the axial direction of the air flow. Thus the fiow of fuel into the air stream is actuated by the suction effect of the air stream.

This basic combination of air throttle valve and single fuel jet as constructed heretofore has not been found to operate satisfactorily under all Operating conditions. lt has been found necessary, therefore, to add one or more adjustable fuel jets to the basic combination to meet all the different Operating conditions. For example, one fuel jet may function primarily for high speed fuel supply and a second fuel jet may be adapted to function primarily for low speed fuel supply. In addition, it has been found necessary to add a choker valve to the basic carburetor combination upstream from the fuel jets. The choker valve increases the richness of the fuel mixture for starting the engine by shutting off the airstream partially and thereby creating a vacuum effect to cause increased fuel fiOW; V

The present invention is based on the discovery that by providing certain relationships in the basic combinaltion of an air throttle and a single fuel jet, the basic combination may serve its purpose even more efiectively than more elaborate carburetor'combinations and do so under all Operating conditions. It has also been found that such a basic combination may be connected directly to a fuel pump. Thus the invention not only eliminates the necessity for multiple jets and the necessity for an auxiliary choker valve, but also eliminates the need for the usual fuel bowl and the usual float-controlled valve associated with the fuel bowl. In addition, the invention eliminates the need for restricting the intake air passage to form a venturi throat.

The invention serves its purpose by providing a mechanically actuated fuel-metering valve on the downstream side of the air throttle valve, not the intake side, and by arranging for the fuel-metering valve to direct the fuel jet counter to the intake air stream, that is, not in the same direction as the airstream. Preferably the fuel metering valve introduces the fuel into the air intake stream laterally thereof and provides what may be termed the invention is employed on the engine of an automobile,

Z,802,fi51 Patented Aug. 13, 1957 ICC stream a component of motion counter to the air stream. It has been found' that opposing the injecting fuel stream to the intake air stream results in maximum efilciency in the intermixing of fuel and air. It has been further found that this efi'iciency may be maintained under all Operating conditions, including engine starting conditions, by properly correlating the action of the fuel-metering valve with the air throttle valve.

A feature of the preferred practice of the invention is the interlinking of the air throttle valve with the fuel metering valve to attain the desired correlation between the two valves. A further feature is the provision of an interconnectinglinkage for this purpose that permits the operation or range of operation of one of the two valves to be adjusted Or shifted relative to the other, thereby to provide any desired relationship between the positions of the two valves in the course of their concurrent operation.

If desired, a second fuel-metering Valve may be used, operated either manually or automatically, to introduce additional fuel into an engine equipped with the carburetor of the present invention. This second .valve wouldbe provided for ease of starting the engine under low temperature conditions.

The various features and advantages of the invention may be understood from the following detailed description considered With the accornpanying drawing.v

In` the drawing, which is to be regarded as merely illustrative Figure 1 is a side elevation of the presently preferred' embodiment of the invention with parts broken away to reveal concealed structure.

Figure 2 is a transverse sectional view of the carburetor shown in Figure 1;

Figure 3 is an axial sectional view of the carburetor;

Figure 4 is a perspective VView of the Valve member used in the fuel metering valve in the preferred embodiment of the invention; and

Figure 5 is an enlarged detail of Figure 1.

Figure 1 shows a carburetor having a body or housing 10 mounted on an internal combustion engine indicated at 11, the housing having a base flange 12 engaged by cap screws 13. The intake end of the carburetor housing provides a cylindrical wall 14 and a circnmferential flange 15 to permit an air cleaner Or filter 16 to be mounted telescopically on the cylindrical wall in abutment against the flange. i

As best shown in Figure 3, the principal parts of the carburetor comprise an air throttle valve 20 of the butterfiy type and a fuel metering'valve, designated as a whole by numeral 21, these two valves being operatively interconnected by suitable linkage. It will be readily understood by those skilled in the art that these two valves may be constructed, arranged, and operated in various ways to carry out the underlying inventive concept.

In the particular construction shown in the drawing, the air throttlevaive 20 is in the form of the usual disc 22 and, in this instance, the disc is mounted on a rocker shaft 23. The rocker shaft 23 extends through the carburetor housing 10 on both sides and is journaled in a pair of'diametrically opposite bores 24 in the housing wall. To keep the rocker shaft from shifting longitudinally, a pair of collars 25 may be fixedly mounted on the shaft in abutment with the opposite sides of the carburetor housing 10, as shown in Figure 2.

The rocker shaft 23 may be adapted for actuation in any suitable manner. In the present arrangement, for example, arocker arm 29 is mounted on the rocker shaft and is adjustably fixed thereon by a suitable Vset screw 30. The outer end of the rocker arm 29 is connected by a pivot pin 31 with the end of an Operating rod 32. When 3 the operating rod 32 is operatively connected to the usual foot throttle or acce'ierator for actuation thereby.

Preferably the carburetor provides for by-pass flow around the air throttle valve 20 in the closed position of the valve when the engine 11 is idling. In this regard, a feature of the invention is the provision of notch 35 in the edge of the valve disc to form such a by-pass atthe closed position of the disc and the further provision of an adjustment screw 36 in the housing 10 adjacent the notch to vary the effective cross-sectional area of the by-pass passage. The notch 35 may be V-shaped and the adjustment screw 36 may have a conical nose 37V conforming to the configuration of the notch as shown in Figure 2.

The fuel metering valve 21 comprises essentially a passage means in combination with an elongated tapered valve member. The passage means may be in the form of a bushing or sleeve 39, and the valve member may be in the form of tapered pin or rod 40 positioned longitudinally in the passage means and adapted for longitudinal movement therein. In the present construction, as best shown in Figure 3, the passage means 39 is mounted in the manner of a liner inside a fitting 41 that is threaded into the side of the carburetor housing lt). The fitting 41 is adapted for connection to a fuel line tube 42 which, in turn, is connected to a suitable fuel source. In the preferred practice of the invention it is contemplated that the tube 42 will be connected to the discharge side of a fuel pump so that the fuel will be supplied to the passage means 39 under suitable pressure. The fitting 41 may be of a well known type having a confined ring 45 and a connecting nut 46, the fiared end 47 of the tube 42 being clamped against the conical surface of the confined ring 45 by overhanging portions of the connecting nut.

The tapered rod-like valve member 4% preferably extends completely across the main air intake passage th of the carburetor with the outer end of the valve member extending outside the housing w. Preferably the rodlike valve member is slidingly mounted in guide bushing 51 that is mounted in the wall of the housing in diametrical alignment with the valve passage means 39. The outer end of the red-like valve member 40 may be adapted in any suitable manner for connection with suitable actuating mechanism. In this instance, the outer end of the rod-like valve member is bent back on itself to form a suitable loop or eye 52 to serve this purpose as will be further explained.

The tapered portion at the inner end of the rod-like valve member 46) reciprocates in the passage means or sleeve 39 for Variable restriction of the passage means to control the rate of fuel flow therethrough. Preferably the range of movement of the rod-like valve member includes a position in which a full-diameter portion of the valve member adjacent the tapered portion extends into the bushing 39 to nearly cut off flow through the bushing, the fuel flow being thereby restricted to a desired rate for idling the engine. In the preferred practice of the invention, it is contemplated that the valve member 40 will be retractible from this limit position through an extensive range of positions to progressively increase the freedom for fuel flow through the bushing 39, the Valve member having a second limit position at which only the tip of the valve member extends into the bushing for maximum rate of fuel flow.

A feature of the preferred practice of the invention is that the red-like valve member 40 is tapered towards its inner end by cutting away the material on one side of the valve member to provide an inclined face 55 as best shown in Figure 4, the face being inclined both with respect to the axis of the valve member and the axis of the passage formed by the bushing 39. This inclined face 55, which may be aptly termed a deflection face, is turned upstream with respect to the direction of intake air flow through the main passage 50.

It is apparent that the inclined face 55 of the valve member Lit) not only cooperates with the passage means or bushing 39 to vary the rate of fuel supply, but also serves to deflect the issuing fuel stream at an angle against the direction of flow of the air stream. Thus, in Figure 3, the arrows 5'6 indicate the direction of flow of the intake air and the arrow 57 indicates the manner in which the issuing fuel stream is defiected, the fuel stream being given a component of motion counter to the direction of air flow. In various practices of the invention the deflecting face 55 may be curved transversely and/or longitudinally, but in this instance the deecting face is substantially straight or planar.

Any suitable means may be provided for reciprocation of the red-like valve member to achieve various rates of fuel flow and at the same time to hold the deflecting face properly oriented with respect to the direction of the intake air stream. A feature of the present embodiment of the invention is the concept of operatively connecting the metering valve member 40 with the rocker shaft 23 for simultaneous and co-ordinated operation of the air throttling valve and the fuel metering valve.

In the particular arrangement illustrated by the drawing, each of the two collars 25 that are fixedly on the rocker shaft 23 is provided with a radial bore 59 to seat the inner end of a screw of) which functions as an operating arm, there being one such arm on each side of the carburetor. As best shown in Figure 5, the inner end of the screw 60 is formed with a circumferential groove 61 for releasable engagement by a small set screw 62. Normally each set screw 62 holds the screw 60 in rigid non-rotating relation to the corresponding collar 25, but the set screw may be loosened whenever it is desired to rotate the screw 60 for adjustment.

Mounted on each of the screws or Operating arms 60 is a threaded sleeve or nut 65 which is preferably formed integral with a corresponding clevis 64. Each of the two clevises 64 has mounted therein a suitable pivot pin 67 for mounting a yoke 68 straddling the carburetor housing 10 and having its opposite ends pivotally embracing the two pivot pins 67. In this instance, the yoke 68 is a suitable U-shaped Wire member, the two ends of which are looped around the two pivot pins 67. Mounted on the yoke 68 at substantially its midpoint is a suitable collar '70 having a circumferential groove 71 embraced by the loop or eye 52 at the outer end of the valve member 40.

As shown in the drawing, the metering valve member 40 lies in a plane perpendicular to the axis of the carburetor housing w and the yoke 68 is positioned preferably approximately in this plane. Of course, the two pivot pins 67 at the opposite ends of the yoke move in arcs but both of the arcs are in near approximation to this Diane.

The manner in which the carburetor functions for its purpose may be readily understood from the foregoing description. The idling position of the moving parts is shown in Figura 3 wherein the butterfly disc of the air throttle valve 25B is in its closed position and the fuel metering valve member ati is inserted into the passage means or bushing 39 to such extent as to nearly cut off fuel flow, the fuel flow Vbeing reduced to the minimum required for idling the engine. At this closed position of the butterfiy valve, air intake is restricted to the small clearance around the periphery of the butterfly disc including the by-pass provided by the disc notch 35. The screw 36 adjacent the notch 35 may be adjusted to vary the rate of air intakefiow for idling the engine as may be desired.

When the Operating rod 32 rotates the rocker shaft 23 clockwise as viewed in Figures'l and 3 for increase in the supply of air and fuel to the engine, the butterfiy valve is rotated out of the closed position.` The clockwise rotation of the rocker shaft 23 swings each of the two screws 6%* clockwise to shift the yoke 68 to the left, thereby retracting the metering valve member 40 with respect to the passage means or bushing 39. Thus, with increased rate of fiowof the air intake caused by opening action of the butterfly valve, corresponding opening movement of the metering Valve member 40 correspondingly increases the rate of fuel supply to the intake air stream. In this manner, correct proportioning of the fuel relative to the air supply is maintained' under all Operating conditions. Also under all operating conditions, the defiecting face 55 of the metering valve member 40 angles the released fuel stream against the direction of fiow of the air intake. The fuel stream is in the form of a mist and directing the fuel stream against the direction of air fiow causes pronounced turbulence and consequent intermixing of the fuel with the air at maximum efiiciency under all Operating conditions.

In the described manner, the invention correlates the rate of fuel fiow with the rate of air Vintake flow and correlates both of these rates of fiow with the requirements of the engine at all speeds of the engine. Thus, unlike present day carburetors supplied with an acceleration pump, no relatively large fuel charge is injected into the intake of the engine during initial stages of acceleration. Such pumps are necessary in conventional carburetors to insure a fuel supply to the engine as the throttle is opened. Without such a pump initial movement of the throttle would result in merely air being drawn into the engine. These pumps waste fuel, for they result in an extremely rich mixture any time the engine is accelerated.

As should be seen, the carburetor of the present invention does not require such a pump for the fuel required for the throttle opening is automatically introduced at a point between the butterfly and the intake of the engine. Thus no fuel lag is had with the carburetor herein shown and disclosed, for the structure, as hereinbefore explained, correlates the rate of fuel fiow with the rate of air intake fiow and the two rates of fiow are correlated with the engine requirements at all speeds of the same.

If any adjustment of the operation of the two valves relative to each other is required, it is a simple matter to loosen the two small set screws 62 and then to rotate the two screws 60 to vary the distance of the two pivot pins 67 relative to the axis of rotation of the rocker shaft 23. This adjustment varies the '*throw of the yoke 38 in response to rotation of the rocker shaft 23 and thereby varies the range of movement of the metering valve member 40 relative to the range of movement of the butterfly valve 20. This adjustment of the two screws 60 also varies the position of the metering valve member 40 relative to the passage means 39 at the idling position of the two valves.

The carburetor functions without lag in fuel fiow, the responsiveness of the fuel fiow being especially expeditious when the carburetor is used with a fuel pump, as in this instance. As a result, the carburetor provides for quick starting of an engine without the use of a choke and this fact, together with a highly eflicient interrnixture of the fuel with the air, results in considerable fuel saving. The carburetor requires practically no servicing since there are no jets to clog, the fuel being handled entirely by a self-cleaning, metering valve.

If desired or found necessary under low temperature Operating conditions, additional fuel may be introduced into the housing by a second fuel metering valve 73 substantially identical to the fuel metering valve 21. The fuel metering valve 73 may include a fitting 74 adapted for connection to a fuel line 75 by means identical to that used to connect the fuel line 42 to the fitting 41. The fuel lines 42 and 75 can be connected through some suitable Y or like coupling to a pressurized fuel source such as a fuel pump. The fitting 74 mounts a sleeve-like member 76 presenting passage means receiving an elongated tapered valve member 77 identical to the valve member 40. The valve member 77 also extends completely across the main air intake passage 50 of the 'cari buretor with the outer end of the valve member extending beyond the housing 10. The outer extending end of the valve member 77 may be adapted in any manner desired for connection to some suitable actuating mechanism. This actuating mechanism may consist of a flexible cable or the like leading to the driveris compartment of the vehicle to permit manual operation of the valve member or leading to some instrumentality for automatic operation of the valve member under the required operating conditions.

It will 'be vseen that here again the tapered portion at the inner end of the valve member 77, as it is moved longitudinally of the passage means 76, will control the rate of fuel fiow therethrough. As in the first fuel metering Valve descrbed, the range of movement of the valve member 77 includes a position in which the full diametered portion of the member extends into the sleeve 76 to substantially stop the fiow of fuel through the passage means.

The inclined face 78 of the valve member 77 again acts as a deflection surface so that fuel passed through the passage is deflected in a direction opposite to the direction of intake fuel air fiow through the main passage 50. Thus, here again the inclined face 78 not only cooperates with the passage means of sleeve 76 to vary the rate of fuel supply, but also serves to bring about better inter-mixing of the fuel introduced into the fuel-air mixture moving through the main passage 50.

It will thus be seen that the present carburetor provides means for increasing the fuel value of the fuel-air mixture supplied to the engine for ease of engine starting under low temperature operating conditions without the use of any device for choking of the air intake into the engine.

While the carburetor is extremely simple in construction and operation, it may beread'ily used on automobiles, trucks, tractors, and airplanes without the necessity for modification in each instance. It is merely necessary to provide a carburetor of proper diameter for each installation, a carburetor of approximately 11/2 inch inside diameter being satisfactory for use on a typical light automobile. If desired, a gang of such carburetors may be used side by side for operation in unison, each being associated with a separate intake passage.

My description in specific detail of the presently preferred embodiment of the invention will suggest to those skilled in the art various changes, substitutions and other departures from my disclosure that properly lie within the spirit and scope of the appended claims.

I claim:

1. A carburetor for creating a fuel mixture in the air intake of an internal combustion engine; comprising: a housing forming a main passage for the intake air stream; a rocker shaft extending across said passage from the exterior of the housing; a butterfly valve on said rocker shaft to throttle the intake air stream, said butterfly valve being notched to provide a by-pass around the butterfly valve at the closed position of the butterfly valve; an adjustment screw in said housing adjacent said notch at the closed position of the butterfly valve to vary the fiow capacity of said by-pass; lateral passage means to admit fuel into said main passage; an elongated valve member extending from outside the housing into the housing across said main passage into said lateral passage means longitudinally of the lateral passage means, said valve member having a cross section such as to substantially close said .passage means and having an inner terminal portion of tapered configuration for progressive reduction of its cross section towards its inner end to cause the amount of fuel flow from said lateral passage into said main passage to vary with the longitudinal position of the valve member relative to said lateral passage means, said valve member providing a planar deflecting face of substantial extent inclined relative to the axis of the lateral passage means, said deflecting means extending into said main passage and facing upstream theren to deflect the fuel stream counter to the direction of the air intake stream, said butterfiy valve being just upstream from said lateral passage means whereby air moving through said by-pass intermixes With the fuel defiected as the fuel moves in a direction opposite to the air fiowing through the by-pass; at least one Operating arm on said rocker shaft; and means linking said rocker arm With said elongated valve member for actuation thereof simultaneously with actuation of said butterfiy valve.

2. A carburetor for creating a fuel mixture in the air intake of an internal combustion engine, comprising: a housing forming a main passage for the intake air stream; a rocker shaft extending across said passage from the exterior of the housing; a butterfiy valve on said rocker shaft to throttle the intake air stream; means to actuate said rocker shaft for opening and closing of said butterfiy valve; lateral passage means to admit fuel into said main passage downstream from said butterfly valve; an elongated valve member extending from outside the housing into the housing across said main passage into said lateral passage means longitudinally of the lateral passage means, said valve member having a cross seco za tion such as to substantially close said passage means and having an inne'rterminal portion of tapered configuration for progressive reduction of its cross section towards its inner end to cause the amount of fuel fiow from said lateral passage into said main passage to Vary With the iongitudinal position of the valve member relative to said lateral passage means; two Operating arms positioned respectively on the opposite ends of said rocker shaft; and a' yoke straddling the carburetor housing With the ends of' the yoke connected to the two Operating arms respectively and With the medial portion of the yoke operatively'connectedto said elongated Valve member.

References Cited in the file of this patent UNITED STATES PATENTS 

